Crossflow radiator system



Q Einrte States :atent inventors George K. Bennett Peoria;

Robert R. McCutchen, East Peoria, Illinois Appl. No. 756.854 Filed Sept. 3, 1968 Patented Oct. 13, 1970 Assignee Caterpillar Tractor Co.

Peoria, Illinois y a corporation of California CROSSFLOW RADIATOR SYSTEM 2 Claims, '1 Drawing Fig.

US. Cl ..l

Int. Cl ..F28d 15/00, F01p 1 H02 Field ofSearch 165/1 10,

trrorney- Fryer, Tjensvold, feix, Phillips and Lempio [56] References Cited UNITED STATES PATENTS 2,074,350 3/1937 Wood 165/1 10X 2,170,214 8/1939 Morrow et al. 165/110 3,051,450 8/1962 White et a1. 165/110 3,254,707 6/1966 Ferguson 165/110 3,455,377 7/1969 Hayes 165/110 1,998,695 4/1935 White 123/4154 Primary Examiner-Albert W. Davis, J r.

ABSTRACT: A crossflow radiator system with vent means which acts to enable ready filling of the system with liquid coolant and prevents entry of air into the radiator and end tanks from an associate expansion tank when low pressure is experienced due to low speed operation of the coolant circulation pump.

Patented Oct. 13, 1970 3,533,416

INVENTORS GEORGE K BENNETT, JR.

ROBERT R. M CUTCHEN @J ?JQA PAZL,LV 45- ATTORNEYS I .1 CROSSFLOW RADIATOR SYSTEM in many crossflow radiator systems an engine coolant is contained in a radiator and two end tanks and is continuously circulated during engine operation through the engine and back to the tanks and radiator. Since radiators are most efficiently operated when they are full of coolant to the exclusion of all air it is customary to employ an expansion tank to receive air and provide makeup fluid for the system. Expansion tanks are generally disposed at a higher level than the radiator but in the interest of maintaining a low overall engine profile they are now found located in side by side relationship. This gives rise to problems in venting while the system is being filled with coolant and in periodic inclusion of air into the radiator circulatory system during low or erratic engine and pump speeds.

The manner of operation of the present invention and the several advantages of the system will best be understood from the following specification wherein the invention is described by reference to the accompanying drawing. The drawing is a schematic view of a system including a radiator withiend tanks and expansion tank and a portion of the engine through which coolant is circulated.

The radiator is generally indicated at as having an inlet end tank 12 and an outlet end tank 13. The engine, a portion of which is shown at 14, is provided with a pump 15 and this pump withdraws coolant from the outlet end tank 13 to a conduit l6 and directs it through a conduit 17 into and through the engine block and head in a conventional manner. The fluid after circulating through the engine block and head exits through a conduit 18 by which it is introduced into the end tank 12 as at 19. It is customary in systems of the type just described to employ thermostatic controls with shunt circuits so that the coolant is not circulated through the radiator until i the engine attains a predetermined operating temperature. This, however, does not form a part of the present invention and is therefore not disclosed herein.

An expansion tank or makeup tank is shown at 20 in proximity to the end tank 13 and the function of this tank is to receive air which may for any reason be included in the radia tor and end tanks and also to contain coolant for delivery into the radiator and end tanks for makeup purposes when they include air as a result of leakage, evaporation or some other causes.

One of the problems presented when the makeup tank is provided in side by side relationship with the end tank as shown is that venting of all of the spaces during filling of the system becomes difficult. This is accomplished in the present invention by providing a filling spout 22 with the usual removable cap thereon at the upper end of the makeup tank 20. A vent is then provided which extends from adjacent the upper end of one of the end tanks 12 and 13, here shown as the tank 12, and then extends downwardly to a point which is approximately at the level of the bottom of the expansion tank but above the level of the outlet of the bypass 26. This vent shown in tubular form at 24 extends upwardly from this level as illustrated at 25 to a point adjacent the upper end of the expansion tank 20. To fill the system, coolant is introduced through the filling-spout 22 to fill the expansion tank and meanwhile to pass through a bypass conduit 26 into the line 16 and thence upwardly through the pump and engine as well as upwardly through the end tanks and radiator until the entire system ,is full. Since the end tanks and radiator are vented at the top as well asthe expansion tank by reason of the cap being removed from the'filler spout, no airlock occurs to prevent adequate'tilling. It will be understood that the return line 18 extends at a level above the engine outlet or slopes upradiator and end tanks. Ordinarily this cavitation or inclusion of air will be corrected when liquid in the expansion tank flows through the bypass 26 and is pumped into the circulatory system. However, this requires a considerable length of time during which inefficient heat transfer as well as inefficient pumping will take place because of the cavitation or presence of air in the system. In the present system during ordinary operation at relatively high engine speeds the pump exceeds the necessary capacity for full circulation through the system and a portion of the coolant is being bled off through the vent line 24-25 and into the expansion chamber 20. Thus when there is a tendency for cavitation to occur, air from the upper end of the chamber 20 is prevented from entering the circulatory system through the vent which is filled with liquid and until the requirement for fluid in the system is made up through the bypass 26.

In amplification of the above and by way of example the vent tubes of the prior art terminate at a point right below the top of the tank 20 where tube 24 enters. This arrangement permits venting of air from tanks 12 and 13 as the system is 7 filled with coolant, but does not maintain a full" system at 24 to tank 20.

ward fromthe engine outlet to a level just below the tops of the other tanks to where it enters the end tank 12 at 14.

Another very great advantage of the system disclosed is that As pump P continues to run. Tanks l2 and 13 and the radiator tubes therebetween will become completely filled, provided sufficient coolant is added to tank 20. The flow capacity of the pump is greater than that of the radiator. and if it continues to runat a moderately high speed, excess coolant will be returned to tank 20 by tube 24. Thus adequate venting of tanks 12 and 13 is achieved.

However, if the pump is now stopped, or run at a very slow speed, sufficient coolant pressure in tank 12 will not be maintained and coolant from tank 13 and 12 will flow through tubes 16 and 26 into tank 20 until the coolant level in all three tubes is equalized. Air from tank 20 flows back through tube 24 to tanks 12 and 13. This is a result of the well-known characteristic of fluids tending to seek their own level.

Thus, at slow pump speeds, the radiator may be only partially full of water. The result is that when an engine is idling, a time when the greatest demand is made upon'the radiator and cooling system due to diminished air flow over the radiating elements, it is only partially full.

The subject invention avoids this serious problem. Tube 25 is added to tube 24. During the filling of the system, the subject device functions in a manner similar to that of the prior art as described above. Air from tanks 12 and 13 is vented tov tank, 20 through tubes 24 and 25 as tanks 12 and 13 fill up.

When tanks 12 and 13 are full, the coolant in tank 20 will be at a given level, for example, near the top of the tank. At high pump speeds, excess fluid will be returned to tank 20 through tubes 24 and 25. Thus tube 25 will become filled with fluid.

At low or zero pump speeds, coolant from tanks 12 and 13 cannot flow through tubes 16 and 26 into tank 20 because the coolant retained in tube 25 prevents the venting of air to tanks 12 and 13. Accordingly the system will stabilize when the level of coolant in tube 25 falls to said aforesaid level. Any additional flow of coolant from tanks 13 and 12 to tank 20 would require pulling a vacuum which the system will not do. Thus the radiator is maintained full of coolant at all times, due to utilization of tube 25, which clearly has a marked effect on the operation of the system.

We claim:

1. In a crossflow radiator system for an engine comprising a radiator with two end tanks and an expansion tank all disposed at approximately the same level, a coolant pump driven by the engine and means to direct fluid from the pump through the engine, through the radiator and end tanks, and back to the pump, the improvement which comprises a vent passage extending from adjacent an upper end of one end tank to a point and thenc tank.

2. The improvement setforth in claim 1 with a filler 5 adjacent the upper end of the expansion tank.

pout 

